The goals of this research are to gain a better understanding of the elastic fivers and the veil cells in the human dermis in order to apply this knowledge to studies dealing with aging of skin. Skin biopsies from volunteers will provide materaial for these studies: sun-exposed and sun-protected skin from young and aged healthy persons, and juvenile and mature onset diabetics. We plan to study the three dimensional organization of the human dermal elastic fiber network including individual elastic fibers for their substructure by scanning electron microscopy (SEM). We will study the ultrastructure of the leastic fibers at various levels of their organization by transmission electron microscopy (TEM). We will also attempt to induce the formation of elastin in long term dermal fibroblast cultures as nother model system. Such a tissue culture system may be able to provide insight in to the mechanisms by which elastin synthesis is altered by age, presence of diabetes mellitus, irradiation with UVB or UVA light in the presence of psoralens. We plan to test hypothesies that elastic fiber formation in chronologically aged skin is characterized by fiber degradation and abnormalities of fiber assembly in contrast to actinically damaged skin in which the elastic fibers appear to be formed differently and some of which eventually undergo degradation. We shall survey strains of young and old rats and mice to determine whether alterations in cutaneous elastic fibers similar to those found in humans also occur in rodernts. If so we shall radiolabel elastic fibers in young animals and serially bipsy their skin to determine the sequence of morphological changes. Another goal is to learn more about the veil cell -- a fibroblast-like cell -- that surrounds all the microcirculatory vessels in the dermis. In diabetic skin, actinically damaged skin and in some cases of aged skin, the vascular walls are thickened and the veil cells are prominent. In some cases of aged skin the vascular walls are abnormally thin and the veil cells are absent or underdeveloped. We plan to test the hypothesis that the veil cell is responsible for the vascular wall changes by in vitro autoradiographic techniques. This work should provide data that is applicable to elastic tissue changes in atherosclerosis, lung disease and the angiopathy of diabetes.